function externalLinks() {
 if (!document.getElementsByTagName) return;
 
 var anchors = document.getElementsByTagName("a");
 if (anchors.length > 0){
	 for (var i=0; i<anchors.length; i++) {
	   var anchor = anchors[i];
	   if (anchor.getAttribute("href") &&
	       anchor.getAttribute("rel") == "external")
	     anchor.target = "_blank";
	 }
 }
}
window.onload = externalLinks;